code: def test_windows_cse_excluded() -> None:
      lf = pl.LazyFrame(
          data=[
              ("a", "aaa", 1),
              ("a", "bbb", 3),
              ("a", "ccc", 1),
              ("c", "xxx", 2),
              ("c", "yyy", 3),
              ("c", "zzz", 4),
              ("b", "qqq", 0),
          ],
          schema=["a", "b", "c"],
      )
  
      result = lf.select(
          c_diff=pl.col("c").diff(1),
          c_diff_by_a=pl.col("c").diff(1).over("a"),
      ).collect(comm_subexpr_elim=True)
  
      expected = pl.DataFrame(
          {
              "c_diff": [None, 2, -2, 1, 1, 1, -4],
              "c_diff_by_a": [None, 2, -2, None, 1, 1, None],
          }
      )
      assert_frame_equal(result, expected)
  
imports: import re
  from datetime import date, datetime
  from tempfile import NamedTemporaryFile
  from typing import Any
  import numpy
  import pytest
  import polars
  from polars.testing import assert_frame_equal
label_desc: Use image node_id 8 for calling a global function with example usage: test_windows_cse_excluded() without return types